Dry-pipe sprinkler system.



G. I. ROCKWOOD.

DRY PIPE SPRINKLER SYSTEM.

APPLICATION FILED NOV. 24, 1915.

1 1 99,744 Patented Sept. 26, 1916.

fmwem$az I GEORGE I. ROCKWOOD, 0F WORCESTER, MASSACHUSETTS.

DRY-PIPE SPRINKLER SYSTEM.

Specification of Letters Patent.

Patented Sept. 26, 1916.

Application filed November 24, 1915. Serial No. 63,294.

To all whom it may concern:

Be it known that I, GEORGE I. Rocnwooo;

a citizen of the United States, residing at Worcester, in the county ofWorcester and State of Massachusetts, have invented a new and usefulDry-Pipe Sprinkler System, of which the following is a specification.

Although the so-called dry pipe sprinkler system is largely employed atthe present time, a serious difficulty is presented occasionally whenthis system is used in acold storage plant. It has been found that waterwill condense on the inside of the pipes and owing to the lowtemperature in the cold storage plant will freeze there and eventuallyfill up the pipe, thus preventing its proper operation. I have foundthat this difficulty is due to the fact that the small body ofwater usedfor sealing the valve of is supplied.

the dry pipe vaporizes slowly and the vapor extends throughout the riserpipe and the piping system connected with it.

The principal object of this invention is to prevent the passage ofwater vapor through the riser pipe and the systemand I accomplish thisresult according to the present invention by recondensing the vapor at apoint close to its source and directing it back into the body of waterfrom which it Reference ing drawing, which is a central verticalsectional view ofa portion of a dry pipe sprinkler system showing apreferred embodiment of this invention applied thereto.

The drawing shows the invention as applied to a dry pipe sprinklersystem comprising the usual supply main 10, dry pipe valve 11, airsupply pipe 12 and alarm pipe 13. Ordinarily the riser pipe 14 isconnected directly above this valve but according to this invention aseparate conductor 15 is provided. I prefer to make this in the form ofa cone having its small end connected with the valve and the large endwith the riser pipe 14. Inside this cone is located a conical core 16spaced from the walls and consequently providing an annular'passage forthe air and also, of course, for the water to the system. This core isshown as firmly supported by a rod 17 at the top and bottom is to be hadto the accompanyand preferably is made hollow. Surroundlng this core,but spaced from it, is a condenslng coil 18. Thisis designed to be fedby a pipe 19 from the outside and to discharge at the top through a pipe20 back into this pipe 19. These pipes are kept supphed with waterbymeans of a water tank 21 having a float 22 for operating a valve 23 andkeeping a constant head of water in the tank, which is supplied from asupply pipe 24. It will be noticed that the distance between the core 16and inner surface of the conductor 15 decreases from the bottom to thetop. This is to provide substantially a uniform area in cross section atall levels so that all the vapor passing through cannot fail to comeunder the influence of the condensing coil.

For the purpose of cooling the pipe 19 from a source outside theconductor 15 and thus causing a continuous circulation of cold waterdown through the pipe 19 and up through the condensingcoil, I have showna casing 25 surrounding this pipe 19 and provided with supply anddischarge pipes 26 and 27. This is for cooling purposes and it may besupplied with a cooling mixture, but preferably is supplied with acooling liquid through the pipe 26.

For the purpose of regulating the temperature of the condensing coil Ihave shown a chamber 30 connected with the pipe 19 and provided with adiaphragm 31 there-. 1n, the interior of which is filled with ether or agas or vapor that is readily expansible by heat and not condensableexcept at temperatures below those required here. The temperature of thewater in the chamber 30 surrounding this diaphragm controls thecontraction and expansion of the ether and causes the diaphragm to moveback and forth and operate a rod 32. By means of a bell crank 34 andconnections 35 this operates an arm36 on a valve 37 in the pipe 26.

In this way when the temperature is reduced below the predetermineddegree the flow of cooling liquid through the pipe 26 to the chamber 25will be reduced. I have also shown a thermometer 40 located in aconvenient position and having its bulb in a chamber communicating withthe pipe 19 so as to show at all times the temperature of the liquidpassing into the condensing coil.

As the cooled liquid circulates through the coil 18 any vapor thatarises from the water sealing the dry pipe valve will have to go intothe annular passage in the conductor 15 and be subjected to the actionof the con- (lensing coil. It will be seen, therefore, that thecondensed liquid will flow down the walls of the conductor 15 or of thecore and will drop back into the body of sealing water. This preventsany large quantity of vapor from passing into the riser pipe and thusinto the sprinkler system and main tains the same in a substantially drycondition except when it "is operated. In this simple and inexpensivema'nner water vapor is kept out of the system, and the danger of thepipes becoming stopped by ice is substantially avoided and thus the drypipe sprinkler system is rendered suitable and safe for use in coldstorage plants and the like.

The pipe 19 can be located in one of the cooling chambers of the coldstorage plant which will provide all necessary cooling effect. Althoughthe condensing coil is cooled it will not be frozen by this means.

Although I have illustrated only a single form of the invention I amaware of the fact that modifications can be made therein by any personskilled in the art without departing from the scope of the invention asexpressed inthe claims. Therefore, I do not wish to be limited to thedetails herein shown and described, but

What I do claim is 1. In a sprinklersystem of the dry pipe type, thecombination with a riser pipe normally filled with air, a watersupplying means, and a valve for normally closing connection betweenthem, of means for condens ing the moisture contained in the air in thepipe to prevent the moisture from passing along the pipe and beingcondensed on the inner surface thereof.

2. In a sprinkler system, the combination with a pipe normally filledwith air, a water supply main, and a valve for normally closingconnection between them, of means between said valve and the pipe forcondensing the moisture contained in the air at the end of the pipe.

3. In a dry pipe sprinkler system, the combination with a riser pipe, asupply main, and a valve for normally closing connection between them,of means between said valve and the riser pipe for condensing themoisture contained in the air passing to the riser pipe, and directingit back toward said valve.

4. The combination with a sprinkler system of the drypipe type, of aconductor at the inlet end thereof having a narrow space for the air,and a condensing coil located in said space.

5. In a sprinkler system of the dry pipe type the combination with ariser pipe, of a conical conductor at the inlet end thereof having anannular space for the air, and a condensing coil located in said annularspace.

6. In a sprinkler system of the dry pipe type the combination with aconductor having an annular space for the air, a condensing coil locatedin said annular space, a pipe for conducting a cooling liquid to thebottom of said coil, and a pipe for conducting liquid away from the topof the coil, said pipes being connected outside. the conductor.

7. In a sprinkler system, the combination with a conical conductor, of aconical core in said conductor forming an annular space therewith forthe passage of air, a coil located in said space, a pipe for conductingwater into the bottom of said coil outside the conductor, means forcooling the water in said pipe before it passes into the coil,

means for conducting the water from the other end of the coil back tothe pipe above said cooling means, and means for maintaining a fullsupply of water in said pipes and coil.

8. In a sprinkler system of the dry pipe type, the combination with asupply main, and a riser pipe, of a conductor connecting them, saidconductor having a space extending therethrough provided with a crosssectional area substantially equal to the area of the supply main, andmeans in said space for condensing vapor in the air therein.

9. In a sprinkler system of the dry pipe type, the combination with asupply main, and a riser pipe, of a conductor connecting them, saidconductor having slanting walls and having a space extendingtherethrough provided with a cross sectional area substantially uniformfrom one end to the other and substantially equal to the area of thesupply main, and means in said space for condensing vapor in the airtherein and allowing it to run down said slanting walls.

-10. In a sprinkler system of the dry pipe type, the combination with aconductor, of a condensing coil located in said conductor, a pipe forconducting the liquid into said condensing coil, a chamber surroundingsaid pipe, means for conducting a cooling liquid into said chamber, andmeans whereby when the temperature of the liquid in said pipe gets downto a predetermined minimum the rate of-flow of the cooling liquid tosaid chamber Will be reduced.

11. In a sprinkler system of the dry pipe type, the combination with aconductor having an annular space for the air, of a condensing coillocated in said annular space, a pipe for conducting the liquid intosaid condensing coil, a chamber surrounding said pipe, means forconducting a cooling liquid into said chamber, a casing to Which saidpipe is connected, a diaphragm located in 5 said casing and having anexpansible fluid behind it, a valve for controlling the supply ofcooling fluid to said casing along said con- GEORGE I. ROCKWOOD.

